The Paris prosecutor’s office has launched an investigation into the French-Swiss concrete company LafargeHolcim supposedly involved in financing Daesh via its plant in Syria.

Three judges of the Paris prosecutor’s office have taken up a case to establish the framework of the company’s activities in Syria, France Inter radio reported.

The company is suspected to have cut a deal with armed groups in the war-torn country, Daesh among them, to keep its new plant in Jalabiya, close to Aleppo, running during the years of the civil war in Syria.

The judicial inquiry was opened on June 9. Two judges will investigate the economic background of the deal, and another one the suspected links with terrorist organizations.

In November, former employees of the company and human rights groups filed a complaint accusing the former employer of financing terrorism and involvement in crimes against humanity. The complaint was never treated up until the current investigation was open. After an internal inquiry, LafargeHolcim admitted that “inappropriate practices” took place and that it allocated hundreds of thousands dollars in 2013 and 2014 to its intermediaries in order to coax the armed groups. The CEO of the company, Eric Holsen, resigned in April, but denied any allegations.

The concrete producer bought the factory in need of huge investment in 2007, and became one of the biggest foreign investors in the country. In 2014 the plant was finally closed.